甘露糖腙重量法在魔芋粉葡甘聚糖含量测定中的应用研究

Study on the Method of Weighing Mannose-hydrazone for Determining Content of Glucomannan in Konjac Powder

通过对甘露糖腙重量法测定魔芋葡甘聚糖 (KGM )含量的影响因素的研究 ,确定了测定条件和该方法的可行性。结果表明 ,魔芋粉取样量 0 .5 0～ 0 .5 5 g ,加体积分数 2 .5 %盐酸2 5mL ,沸水浴水解 3h ,水解液过滤 ,用 0 .4kg/LNaOH调 pH 5 .0 ,再用体积分数 2 0 %醋酸调pH 3.0 ,加苯肼试剂 1.0mL ,室温反应 18～ 2 0h的测定条件适用于KGM测定。经过与比色法比较 ,2种方法测定结果无显著性差异 (P >0 .0 5 )。

The method of weighing mannose-hydrazone was used to determine the content of glucomannan in konjac powder.The factors affecting determination were studied in the experiment. The conditions for determining were made clear and the method was proved to be feasibility by the experiment. The results show that condition of 0.50～0.55g sample for determining, being added 2.5%HCl 25?mL, hydrolyzed for 3 hours at boiling water bath, hydrolyzate being filtered, pH being adjusted to 5.0 by 0 4?kg/L NaOH, then 3.0 by 20% acetate, and reaction with 1?mL benz-hydrazine for 18～20 hours at room temperature is suitable for determining of KGM. Compared with spectrophotometry the results from the two methods were not notable different(P>0.05).